LAUSR

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Transvenous implantation of pacemaker is performed with fluoroscopy for leads’ insertion and implantation in the heart. This implies radiation exposure for patients and operators. Fluoroscopy allows a two-dimensional view of lead movements, and sometimes it is difficult to implant lead in the complex heart anatomy, or in alternative right ventricular (RV) pacing sites, that often requires higher radiation doses. These alternative pacing sites may prevent pacing-induced ventricular dysfunction. They are his bundle pacing area (HBP), ventricular septum close to the conduction system area (VS), RV outflow tract (RVOT). The use of three-dimensional-electroanatomic mapping system (3D-EAM) may reduce fluoroscopy and guide lead implantation. Published median fluoroscopy data for similar procedure are: 6 mGy (1), 13 mGy and 231 microGy/m2 (2). Purpose of this study is to seek out if a 3D-EAM-guided transvenous implantation into RV alternative sites pacing in paediatric patients can be accomplished with zero or near-zero X-rays. Methods Retrospective analysis of children and adolescents with congenital or acquired (idiopathic) complete atrioventricular block (CAVB) without other congenital heart defects who underwent 3D-EAM-guided pacing in alternative RV sites. The implant procedure was divided in 4 steps: 1-contrast venography; 2- 3D mapping: with a steerable catheter (femoral vein), the 3D-EAM acquired geometric reconstruction of the right heart and a pacing map identified RV sites with narrower paced QRS; 3-axillary vein puncture; 4-lead and pacemaker implantation: 3D-EAM guided stylet-directed screw-in lead implantation toward desired RV sites. Data are reported as median (25th-75th centiles). Results 54 CAVB patients (42 females), underwent 3D EAM-guided pacing (27 VVIR, 27 DDD) at age 11.5 (7.7-14) years, weight 42 (26-54) kg. Pacing sites were: 10 HBP, 4 RVOT, 40 VS (Figure 1). Procedure time was 170 (143-193) min, total fluoroscopy exposure and that of the 4 steps are reported in Table 1. The lowest exposures were: 0.2 mGy, 8 microGy/m2 (VVIR) and 0.6 mGy, 15 microGy/m2 (DDD). Paced QRS was 115 (100-120) ms. Conclusions 3D-EAM-guided alternative RV pacing sites was accomplished with very low fluoroscopic exposure, close to zero in some cases. Therefore, with 3D-EAM we can significantly reduce radiological doses also in difficult pacing procedures in paediatric patients, thus reducing radiological risks and preserving ventricular function. The dream is becoming reality. figure 1 table 1